(a) Field of the Invention
The present invention refers to an apparatus for providing a mechanically selectable trigger interval in flywheel magnetos.
(b) Prior Art
Flywheel magnetos are usually made for coaction with so-called electronic ignition circuits. A magnetic core is usually arranged with two or more legs having different windings on the respective leg for coaction with the passing magnets on the flywheel. In such construction, one of the legs carries a winding for generating trigger pulses to trip the current circuit of a thyristor-controlled capacitor used in electronic ignition current circuits. It is very important to mechanically position the legs in relation to the magnets so that triggering is obtained at the desired point in a revolution. U.S. Pat. No. 3,599,615 deals with this problem, and in it the pole surfaces of the leg carrying the trigger winding are specially formed to obtain the desired triggering function. It is, however, expensive to form special magnetic cores for each type of engine so that the trigger function occurs at the desired point in a revolution. Furthermore, it is difficult to determine the triggering points mechanically, and adjustment must always be available on the magnetic core for suiting it to the associated engine in question.